1. Field of the Invention
The present invention relates to a melt extrusion processing method of a thermoplastic resin having a high flow temperature. According to the present invention, even when extrusion processing is conducted continuously for relatively long period of time, there is obtained an extruded article which has not been degraded in an extruder and contains small amount of discolored and degraded materials.
2. Description of the Related Art
Thermoplastic engineering plastics are widely used in electric appliances and electronic parts, OA and AV parts, automobile parts and the like in virtue of their excellent heat resistance and mechanical properties.
These articles are produced from raw material pellets by various molding methods, and it is general to conduct extrusion-processing using a melt kneading type extruder in production of the above-described raw material pellets and in article production from these pellets. Since the thermoplastic resin is exposed to high temperature in an extruder, a part of the resin sometimes remains in the extruder and is degraded with a lapse of extrusion processing time and the resin remained and degraded in the extruder is sometimes contained in an extruded article resulting as a discolored and degraded material to cause disadvantages.